/**
 * @file   hello.cpp
 * @author student <3200300844@zju.edu.cn>
 * @date   Wed Sep 22 19:06:09 2021
 * 
 * @brief  A demo program teaching.
 * 
 * 
 */


#include <iostream>

/**
 * main function.
 *
 * @param argc number of shell parameters.
 * @param argv strings for all parameters.
 *
 * @return system signals.
 */
int main(int argc, char* argv[])
{
  /// Just a demo.
  std::cout << "Hello World!" << std::endl;
  return 0;
}
